1. Field of the Invention
The present invention relates to a motor unit including an electric motor, and to a recording disk driving device including the motor unit.
2. Background Art
Conventionally, a recording disk driving device such as a hard disk device includes a spindle motor (hereafter referred to as “motor”) for rotationally driving a recording disk. As a result of miniaturization of the recording disk driving device in recent years, the motor as a driving source is required to be miniaturized and thinner. In such a motor, a sheet-shaped member, such as a flexible printed circuit board (hereafter referred to as “FPC”) or a name plate, is stuck on an outer face of the motor (i.e., the face of the base portion opposite a side to which a stator is mounted).
When the recording disk is mounted to the motor, the recording disk is normally placed on a rotor hub of the motor placed on a jig and the recording disk is screwed onto the rotor hub by a clamp member. At this time, a downward load is applied on the rotor hub and a bearing of the motor is pressed toward a surface of the jig.
In the case in which the FPC is annular and is stuck to the bottom face of the motor, the FPC is mainly abutted against the jig when the motor is placed on the jig. As a result, that part of the base portion provided with the bearing is positioned above the surface of the jig (See FIG. 7).
If the recording disk is mounted to such a motor, the portion of the base portion provided with the bearing is deformed due to the load applied to the rotor hub. In other words, the portion of the base portion provided with the bearing may bend downward in some cases. As a result, a height of the rotor hub from the base portion and parallelism between them may change, and a relative position of the recording disk with respect to a magnetic head may be displaced in some cases.
In a small motor, it is not easy to stick the FPC onto a predetermined position of the bottom face of the base portion. Therefore, it is required that positioning is carried out easily in sticking of the FPC to enhance efficiency of sticking operation.